The present invention relates to front projection screen assembly for displaying images projected thereon by means of an image projector. Front projection screens have been known for centuries, and for the past century they have been widely used for public display of moving images. Recently, however, the falling costs of image projectors and the availability of appropriate electronic storage media, such as DVD, have created a growing interest in what is commonly referred to as home cinema. Also, the falling costs have made projection systems a natural part of modern meeting rooms and smaller auditoriums.
Evidently, a front projection screen of high quality comes as a natural part of such a home cinema or of the projection system in such a meeting room or smaller auditorium. Since, however, most of the time the projection screen is not in use, there is often a demand for screens which are inconspicuous when not in use. Making the projection screen inconspicuous when not in use, traditionally involves rolling it up, or folding it together, in order make the apparent area smaller, or even to make the projection screen able to be stowed somewhere else.
The need to be able to roll up the screen, however, poses some technical problems in respect of screen quality. One such problem stems from the fact that the screen must be flexible. Unlike a rigid screen, a flexible screen is prone to have deformations such as e.g. wrinkles, undulations or bends over the surface or along the border because of different tension forces across the screen, when it is in the rolled-out state. Also when the screen is rolled up on a drum or a roller, the inner windings may come under pressure causing semi-permanent deformations of the screen, which will be visible the next time the screen is rolled out.
Japanese application 2001-228545 (Nishitani Masatake et al) addresses the above problems. In relation to the wrinkles or undulations it suggests slitting the screen material along the vertical sides of the screen. In relation to the semi-permanent deformations it suggests a buffer or transition material in connection with the winding drum, so that the level difference does not propagate to the outer windings and deforms them.
Whereas traditional cinema is traditionally viewed in a darkened room, this is not necessarily the case for home cinema. Thus, also in use, there is a need for the front projection screen to be inconspicuous and aesthetically pleasing. The same would be the case if the front projection screen is used in a meeting room, where the viewers might need light to take notes and do other work-related things.